docs(v2.3): document how agents see Scarf projects

Three doc updates covering the AGENTS.md context-injection
pattern introduced in the previous commit.

CLAUDE.md — new "Project-scoped chat + Scarf-managed AGENTS.md
context (v2.3)" subsection under Project Templates. Covers:

- The session-project sidecar at ~/.hermes/scarf/session_project_map.json
  (why it exists, what manages it)
- How Hermes picks up project context: cwd-based auto-load of the
  first matching context file (priority order, 20KB cap)
- Exact marker format and block shape
- Invariants that future edits must preserve: secret-safe,
  idempotent, bounded-region, non-fatal, refresh-before-session-start
  ordering
- Template-author contract: leave the region alone, put
  instructions below
- Known caveat: parent-directory `.hermes.md` shadowing (deferred
  to v2.4)

scarf-template-author SKILL.md — new pitfall bullet in the
"Common pitfalls" checklist telling scaffolding agents to
preserve the `<!-- scarf-project -->` region and put template-
specific instructions below it. Rebuilt the bundle so installs
from the catalog pick up the guidance; regenerated catalog.json.

Wiki update (Project-Templates page) lands next via scripts/wiki.sh.

93/93 Swift + 24/24 Python tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -142,6 +142,42 @@ Key services: [TemplateConfig.swift](scarf/scarf/Core/Models/TemplateConfig.swif
 
 **Schema is Swift-primary.** If `TemplateConfigField.FieldType` gains a new case, update in order: `TemplateConfig.swift` (model + validation), `tools/build-catalog.py` (`SUPPORTED_CONFIG_FIELD_TYPES` + type-specific rules), `widgets.js` (`summariseConstraint`), `TemplateConfigSheet.swift` (new control subview), tests on both sides. Schema drift between validator + installer is the kind of bug users only notice after shipping.
 
+### Project-scoped chat + Scarf-managed AGENTS.md context (v2.3)
+
+v2.3 adds a per-project Sessions tab and a "New Chat" button that spawns `hermes acp` with `cwd = project.path`. Session-to-project attribution is persisted in a Scarf-owned sidecar at `~/.hermes/scarf/session_project_map.json` — the ACP wire protocol has no project-metadata hook (extra params are silently dropped), and `state.db` has no cwd column, so the sidecar is Scarf's source of truth for "which project does this session belong to?" Managed by [SessionAttributionService.swift](scarf/scarf/Core/Services/SessionAttributionService.swift); read by the per-project [ProjectSessionsView.swift](scarf/scarf/Features/Projects/Views/ProjectSessionsView.swift).
+
+**Giving the agent project awareness.** Hermes auto-reads a context file from the session's cwd at startup — priority order `.hermes.md` → `HERMES.md` → `AGENTS.md` → `CLAUDE.md` → `.cursorrules`, first match wins, 20KB cap. We lean on that by writing a Scarf-managed block into `<project>/AGENTS.md` before opening the session. Service: [ProjectAgentContextService.swift](scarf/scarf/Core/Services/ProjectAgentContextService.swift). Block shape:
+
+```
+<!-- scarf-project:begin -->
+## Scarf project context
+_Auto-generated by Scarf — do not edit between the begin/end markers._
+
+You are operating inside a Scarf project named **"<Project Name>"**. …
+
+- **Project directory:** `<absolute path>`
+- **Dashboard:** `<path>/.scarf/dashboard.json`
+- **Template:** `<author/id>` v<version>    <!-- template-installed only -->
+- **Configuration fields:** `field_a`, `field_b (secret — name only, value stored in Keychain)`
+- **Registered cron jobs:** `[tmpl:<id>] <name>` — schedule …, currently paused|enabled
+- **Uninstall manifest:** `<path>/.scarf/template.lock.json`  <!-- when present -->
+
+Any content below this block is template- or user-authored; preserve and defer to it.
+<!-- scarf-project:end -->
+```
+
+**Invariants.**
+
+- **Secret-safe.** Block surfaces field NAMES, never VALUES. A project with a Keychain-stored secret shows `api_token (secret — name only, …)`; the Keychain ref URI and any plaintext value never appear. Auditable by `refreshListsFieldNamesNotValues` in `ProjectAgentContextServiceTests`.
+- **Idempotent.** Two refreshes with unchanged state produce byte-identical output. The write is skipped entirely when no delta, avoiding file-watcher churn.
+- **Bounded.** Everything outside the markers is preserved on every refresh. Template-author AGENTS.md content lives safely below the block.
+- **Non-fatal.** `ChatViewModel.startACPSession` calls refresh with `try?` + log — a failed write doesn't block the chat from starting; worst case is the session loses project awareness.
+- **Refresh timing.** Called BEFORE `client.start()` so the block lands before Hermes's session-boot context scan. Skipping this ordering = the agent sees stale context from the previous refresh (or nothing, on fresh projects).
+
+**Template-author contract.** A template shipped via the catalog should include an `AGENTS.md` with the template's operational instructions. Authors leave the `<!-- scarf-project -->` region alone — Scarf populates it at chat-start time. Everything below is template-owned and preserved.
+
+**Known caveat.** If any parent directory of the project contains `.hermes.md` or `HERMES.md`, those shadow the project's `AGENTS.md` (higher in Hermes's priority order). No fix in v2.3 — deferred to v2.4 pending user input on how to handle authored `.hermes.md` files.
+
 ## Template Catalog
 
 Shipped community templates live at `templates/<author>/<name>/` (one level down — `templates/CONTRIBUTING.md` explains the submission flow for authors). The catalog site is generated from this directory and served at `awizemann.github.io/scarf/templates/` alongside the Sparkle appcast — the two coexist on the `gh-pages` branch but touch completely disjoint paths.