feat(acp): bring your own harness (BYOH) — generic ACP runtime seam + settings gallery (#2773)

## What

Implements a "bring your own harness" (BYOH) generic ACP mechanism —
replacing per-harness backend code with a data-driven 3-tier system:

- **Tier 1 (compiled-in builtins):** goose, claude, codex, buzz-agent —
unchanged behavior
- **Tier 2 (bundled presets):** cursor, omp, grok, opencode, kimi, amp,
hermes, openclaw, and any future additions — defined in
`PRESET_HARNESSES`, no code duplication, icons stay
TerminalSquare/bundled-asset-only
- **Tier 3 (user-defined custom):** JSON definitions saved to
`custom_harnesses/` under app data; managed via Settings → Agents UI

## Changes

### Core data model
- `HarnessDefinition` — id, label, command, args, env, install URL/hint
- `PRESET_HARNESSES` static table — single source of truth for all
presets; `preset_harness_ids()` derives reserved IDs (D-11: no
hand-maintained copy)
- `source: "builtin" | "preset" | "custom"` tagging on every catalog
entry

### Persistence (B-4, B-6)
- `save_custom_harness_to_dir(dir, definition, rename_old_id)` —
backup-swap atomic write (backs up target → .bak, commits temp → target,
restores .bak on failure, removes .bak on success); safe on Windows
where `fs::rename` over an existing file is "access denied"
- `save_and_warm` / `delete_and_warm` — hold `PERSIST_MUTEX` for the
write + registry-warm pair, eliminating the lost-update race (B-6) where
two concurrent saves could interleave their warm calls and leave a stale
registry snapshot
- Validate-before-mutate: both IDs and env validated before any
filesystem mutation

### Env validation boundary (B-3)
- `validate_harness_definition_pub` calls `validate_user_env_keys` on
definition env at save AND load
- Rejects malformed keys (BUZZ_AUTH_TAG=x forgery shape), reserved keys
(BUZZ_MANAGED_AGENT etc.), NUL bytes, oversized values

### TypeScript boundary (B-2 / Thufir CRITICAL)
- `RawAcpRuntimeCatalogEntry` now declares `definition_env?:
Record<string,string>` and `source: "builtin" | "preset" | "custom"`
- `fromRawAcpRuntimeCatalogEntry` maps `definition_env → definitionEnv`
(camelCase); absent field defaults to `{}`
- Edit form reads `entry.definitionEnv` — env no longer erased on
save-then-edit cycle

### Unified descriptor (Phase A / Thufir F4)
- `EffectiveHarnessDescriptor { command, args, env }` in `readiness.rs`
- `resolve_effective_harness_descriptor()` — single resolver used by
spawn, spawn_hash, summary, get_agent_models (both saved and unsaved),
and readiness
- No competing arg-resolution forms

### Other fixes
- B-5: stop freezing `runtime.defaultArgs` into `record.agent_args` on
normal create paths
- B-7: readiness exec-check — `MissingBinary` variant for custom
commands not found on PATH
- B-8: onboarding transition — `setTimeout(0)` removed, parent-owned
route intent via `navigateAfterComplete` prop
- C-9: collector-discriminating sweep tests with injectable filters
- C-10: `HarnessManagementCard` uses `harnessGalleryLogic` helpers
(killed duplicate filter/sort)
- D-11: `BUILTIN_IDS` derived from `PRESET_HARNESSES` (no
hand-maintained copy)
- D-12: `mobile/pubspec.lock` churn reverted
- D-13: false ownership fast-path comment fixed
- D-14: URL scheme validation for `installInstructionsUrl`
- D-15: OpenClaw Gateway env-locus README line

### Tests added
**B-4 persistence (6 tests):**
`save_to_dir_create_writes_file_and_loads_back`,
`save_to_dir_same_id_edit_replaces_content`,
`save_to_dir_backup_is_cleaned_up_after_same_id_edit`,
`save_to_dir_rename_removes_old_file_and_creates_new`,
`save_to_dir_rename_nonexistent_old_id_is_non_fatal`,
`save_to_dir_roundtrip_with_env_preserves_values`

**B-3 env validation (6 tests):**
`validate_rejects_malformed_key_with_equals_sign`,
`validate_rejects_reserved_key_buzz_managed_agent`,
`validate_rejects_reserved_key_case_insensitive`,
`validate_rejects_nul_byte_in_value`,
`validate_rejects_value_over_per_value_size_limit`,
`validate_accepts_well_formed_env`

**B-2 API boundary (4 TS tests in tauri.test.mjs):**
`fromRawAcpRuntimeCatalogEntry maps definition_env to definitionEnv`,
`defaults definitionEnv to {} when absent`, `preserves source preset`,
`env round-trips through edit payload shape`

## Preset catalog

| ID | Label | Command |
|----|-------|---------|
| `cursor` | Cursor | `cursor-agent acp` |
| `omp` | Oh My Pi | `omp acp` |
| `grok` | Grok Build | `grok agent --always-approve stdio` |
| `opencode` | OpenCode | `opencode acp` |
| `kimi` | Kimi Code | `kimi acp` |
| `amp` | Amp | `amp-acp` |
| `hermes` | Hermes Agent | `hermes-acp` |
| `openclaw` | OpenClaw | `openclaw acp` |

## Review-fix pass (2026-07-26, Eva)

Fixes from the three-way review (Wren / Dawn / Eva) in the
buzz-generic-acp-harnesses thread, pushed as new commits (no rewrite):

1. **installHint edit round-trip** — form seeding extracted to
`formValuesFromCatalogEntry` (single source of truth), input rendered,
full-definition lossless round-trip regression.
2. **Dangling-delete coherence** — delete allowed; confirm counts
referencing agents (direct pin + persona-inherited); summary rows render
`harness (deleted): <id>`; spawn errors become actionable sentences
(`user_facing_harness_error`); composed delete→summary→start test.
3. **Comma-in-args** — rejected at `validate_harness_definition` (shared
by save AND disk load), mirrored inline in the form.
4. **Registry publish race** — collision/dup filtering moved into
`load_custom_harnesses` (both loaders inherit shadowing rules);
discovery publishes by re-reading the dir under `persist_mutex` (lock
scoped to publish only); deterministic interleaving regressions for
save-during-discovery and delete-during-discovery.
5. **Mechanical** — discarded `belongs_to_us` sweep arg deleted,
`load_global_agent_config` hoisted out of the per-record summary loop,
duplicated doc paragraph + stray SAFETY comment removed.
6. **PGID test de-flaked** — leader kept alive through the assertion.

Known follow-up (filed in review, not blocking): file-size split-outs
queued in `check-file-sizes.mjs` entries.

## Gate table — head `bf53f1d60`

| Gate | Result |
|------|--------|
| `cargo test --lib` (desktop/src-tauri) | **1701 passed**, 0 failed, 14
ignored |
| desktop JS suite (`pnpm test`) | **3605 passed**, 0 failed |
| `tsc --noEmit` | clean |
| `biome check` + file-size/px/pubkey checks | clean |
| `cargo clippy --lib -- -D warnings` | clean |
| `cargo fmt --check` | clean |

PR head: `bf53f1d60e3cbd07392e1287b83bb37ba90d0d33` — includes merge of
origin/main (`c2a4ee711`, conflicts in agent_models composed with
#2890's live Databricks discovery)

---------

Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: tlongwell-block <109685178+tlongwell-block@users.noreply.github.com>
Signed-off-by: Tyler Longwell <tlongwell@block.xyz>
Co-authored-by: npub1mn7jgtj4w2pd0g0zeuhxsa6jy6p0rewxz4kujt98my82ahfmp72sxjexk7 <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@buzz.block.builderlab.xyz>
Co-authored-by: tlongwell-block <109685178+tlongwell-block@users.noreply.github.com>
Co-authored-by: Dawn (sprout agent) <c6237ef84fa537c78dcee78efd2d4e59f728859c7f194da42ac51ededfa0be05@sprout-oss.stage.blox.sqprod.co>
Co-authored-by: Tyler Longwell <tlongwell@block.xyz>
Co-authored-by: npub1qyvc0c5kl4gqv2fd97fsk46tu378sqgy35vc83rvgfwne90sel7s0ed67d <011987e296fd5006292d2f930b574be47c7801048d1983c46c425d3c95f0cffd@buzz.block.builderlab.xyz>

desktop/public/harness-logos/CREDITS.md

@@ -0,0 +1,22 @@
+# Preset harness logos — provenance
+
+Third-party marks bundled to identify tier-2 preset harnesses in the runtime
+gallery (`PRESET_LOGOS` in `desktop/src/features/onboarding/ui/RuntimeIcon.tsx`).
+Nominative use only — each mark identifies its own vendor's harness.
+
+Add a row here when adding a preset logo; only bundle marks whose upstream
+license permits redistribution.
+
+| File | Upstream | Commit | License | Source path | Modifications |
+|---|---|---|---|---|---|
+| `hermes.png` | [NousResearch/hermes-agent](https://github.com/NousResearch/hermes-agent) | `6ad632b` | MIT © 2025 Nous Research | `website/static/img/logo.png` | Cropped the baked-in border frame, padded to square, resized to 64×64, quantised to a 16-colour palette |
+| `openclaw.svg` | [openclaw/openclaw](https://github.com/openclaw/openclaw) | `b06f40a` | MIT © 2026 OpenClaw Foundation | `ui/public/favicon.svg` | Removed the SMIL animation elements (renders the upstream rest pose statically — verified pixel-identical to the upstream frame at t=0); minified paths |
+| `omp.svg` | [can1357/oh-my-pi](https://github.com/can1357/oh-my-pi) | `667111575ebba136dadfd6989379e7f67e0d40d9` | MIT © 2025 Mario Zechner; © 2025–2026 Can Bölük | `assets/icon.svg` | None |
+| `kimi.png` | [MoonshotAI/kimi-cli](https://github.com/MoonshotAI/kimi-cli) | `4a550effdfcb29a25a5d325bf935296cc50cd417` | Apache-2.0; NOTICE: Kimi Code CLI © 2025 Moonshot AI | `web/public/logo.png` | None |
+| `grok.svg` | [SpaceXAI brand guidelines](https://x.ai/legal/brand-guidelines) | Retrieved 2026-07-25 | xAI Brand Guidelines: marks may be used to accurately refer to xAI or its services; logos must be used exactly as provided | `SpaceXAI_Grok_Assets.zip` → `Grok_Logomark_Dark.svg` | None |
+
+`amp.png` and `opencode.svg` predate this file; their provenance was not
+recorded when they were added. Cursor intentionally uses the generic terminal
+fallback: Cursor's official brand page offers downloadable assets, but neither
+that page nor its Terms of Service grants third parties permission to
+redistribute them. The previous unproven `cursor.png` was removed.

desktop/public/harness-logos/grok.svg

@@ -0,0 +1,4 @@
+<svg width="1024" height="1024" viewBox="0 0 1024 1024" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M395.479 633.828L735.91 381.105C752.599 368.715 776.454 373.548 784.406 392.792C826.26 494.285 807.561 616.253 724.288 699.996C641.016 783.739 525.151 802.104 419.247 760.277L303.556 814.143C469.49 928.202 670.987 899.995 796.901 773.282C896.776 672.843 927.708 535.937 898.785 412.476L899.047 412.739C857.105 231.37 909.358 158.874 1016.4 10.6326C1018.93 7.11771 1021.47 3.60279 1024 0L883.144 141.651V141.212L395.392 633.916" fill="#0A0A0A"/>
+<path d="M325.226 695.251C206.128 580.84 226.662 403.776 328.285 301.668C403.431 226.097 526.549 195.254 634.026 240.596L749.454 186.994C728.657 171.88 702.007 155.623 671.424 144.2C533.19 86.9942 367.693 115.465 255.323 228.382C147.234 337.081 113.244 504.215 171.613 646.833C215.216 753.423 143.739 828.818 71.7385 904.916C46.2237 931.893 20.6216 958.87 0 987.429L325.139 695.339" fill="#0A0A0A"/>
+</svg>

desktop/public/harness-logos/omp.svg

@@ -0,0 +1,16 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 120 90" width="120" height="90">
+  <!-- Pi symbol with plugin connector -->
+  <!-- Horizontal bar -->
+  <rect x="10" y="8" width="100" height="12" rx="2" fill="#fafafa"/>
+  <!-- Left leg -->
+  <rect x="25" y="20" width="12" height="62" rx="2" fill="#fafafa"/>
+  <!-- Right leg -->
+  <rect x="75" y="20" width="12" height="45" rx="2" fill="#fafafa"/>
+  <!-- Plugin connector -->
+  <rect x="71" y="55" width="20" height="16" rx="3" fill="#f97316"/>
+  <rect x="76" y="59" width="3" height="8" rx="1" fill="#0d0d0d"/>
+  <rect x="82" y="59" width="3" height="8" rx="1" fill="#0d0d0d"/>
+  <!-- Decorative dots -->
+  <circle cx="18" cy="14" r="2" fill="#f97316" opacity="0.8"/>
+  <circle cx="102" cy="14" r="2" fill="#f97316" opacity="0.8"/>
+</svg>

desktop/public/harness-logos/openclaw.svg

@@ -0,0 +1,16 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 120 120" fill="none">
+  <defs>
+    <linearGradient id="a" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" stop-color="#ff4d4d"/>
+      <stop offset="100%" stop-color="#991b1b"/>
+    </linearGradient>
+  </defs>
+  <path d="M60 10C30 10 15 35 15 55c0 20 15 40 30 45v10h10v-10s5 2 10 0v10h10v-10c15-5 30-25 30-45 0-20-15-45-45-45Z" fill="url(#a)"/>
+  <path d="M20 45C5 40 0 50 5 60s15 5 20-5c3-7 0-10-5-10Z" fill="url(#a)"/>
+  <path d="M100 45c15-5 20 5 15 15s-15 5-20-5c-3-7 0-10 5-10Z" fill="url(#a)"/>
+  <path d="M45 15Q35 5 30 8M75 15Q85 5 90 8" stroke="#ff4d4d" stroke-width="3" stroke-linecap="round"/>
+  <circle cx="45" cy="35" r="6" fill="#050810"/>
+  <circle cx="75" cy="35" r="6" fill="#050810"/>
+  <circle cx="46" cy="34" r="2.5" fill="#00e5cc"/>
+  <circle cx="76" cy="34" r="2.5" fill="#00e5cc"/>
+</svg>

desktop/public/harness-logos/opencode.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink" width="512" height="512"><svg width="512" height="512" viewBox="0 0 512 512" fill="none" xmlns="http://www.w3.org/2000/svg">
+<rect width="512" height="512" fill="#131010"></rect>
+<path d="M320 224V352H192V224H320Z" fill="#5A5858"></path>
+<path fill-rule="evenodd" clip-rule="evenodd" d="M384 416H128V96H384V416ZM320 160H192V352H320V160Z" fill="white"></path>
+</svg><style>@media (prefers-color-scheme: light) { :root { filter: none; } }
+@media (prefers-color-scheme: dark) { :root { filter: none; } }
+</style></svg>