fix: refresh stale squad.agent.md greeting version on re-init - #1995

What

Fixes squad.agent.md's first-response greeting literal (backtick-quoted `Squad v...`) staying stamped with a stale version when squad init is re-run against an already-initialized project, even though the HTML comment marker (<!-- version: ... -->) and the Identity - **Version:** line are correctly refreshed on the same re-run.

Why

squad init always calls stampVersion() on an existing squad.agent.md after sdkInitSquad() returns, regardless of skipExisting, to "ensure the version is fully stamped". stampVersion (in packages/squad-cli/src/cli/core/version.ts) and its SDK counterpart stampVersionInContent (in packages/squad-sdk/src/config/init.ts, used when generating a fresh squad.agent.md from the template) each replace three version locations. The first two regexes (<!-- version: ... --> and - **Version:** ...) are written permissively and are idempotent — they match any prior value, resolved or not. The third regex, however, only matched the unresolved `Squad v{version}` placeholder token. Once a real version had been stamped once, the placeholder text no longer existed in the file, so every subsequent re-stamp silently left the greeting literal on whatever version it was last set to.

Not affected: squad upgrade fully rewrites squad.agent.md from the template (which always contains the unresolved placeholder) before stamping, so the placeholder is always present there — the regression is specific to the re-init / skipExisting=true path.

How

Widened the third regex in both stampVersion and stampVersionInContent from matching only `Squad v\{version\}` to matching `Squad v[^`]*` — i.e. anything between `Squad v and the closing backtick. This still matches the unresolved placeholder, and now also matches an already-resolved semver (with or without a prerelease suffix), making the replacement idempotent regardless of the file's current state. Both implementations were kept in sync per existing convention (each package has its own copy of the stamping logic).

Added regression coverage in test/cli/init.test.ts:

• A direct unit test that seeds a stale resolved `Squad v0.9.0` literal (plus stale marker/Version line) and asserts stampVersion() refreshes all three locations.
• A full re-init integration test: runInit() once, mutate the resulting squad.agent.md to simulate an older installed version in all three locations (not the {version} placeholder), runInit() again against the same project (hits the skipExisting=true / existing-file path), and assert every version location — including the greeting literal — now matches the current version.

PR Readiness Checklist

Branch & Commit

• Branch created from dev (upstream/dev, not main)
• Branch is up to date with dev
• PR is in draft mode (by request)
• Commit history is clean (single commit)

Build & Test

• npm run build -w packages/squad-cli passes
• npm run build -w packages/squad-sdk — fails on upstream/dev baseline, unrelated to this change (see Waivers)
• Targeted tests pass: npx vitest run test/cli/init.test.ts (18/18, including 2 new regression tests)
• Adjacent suite passes: test/cli/upgrade.test.ts, test/cli/init-upgrade-parity.test.ts, test/init-sdk.test.ts, test/init.test.ts, test/init-scaffolding.test.ts (all pass in isolation; see Waivers for a flaky test under full-suite parallel load)
• npm test (full suite) — not run to completion; see Waivers
• npm run lint — fails on upstream/dev baseline, unrelated to this change (see Waivers)
• npm run lint:eslint on changed files — 0 errors (63 pre-existing n/no-sync warnings in init.ts, untouched by this diff)

Changeset

• Changeset added via manual .changeset/fix-reinit-stale-version-greeting.md (patch, both @bradygaster/squad-cli and @bradygaster/squad-sdk)

Docs

• N/A — no user-facing/docs change, internal stamping-logic bugfix

Exports

• N/A — no new modules, no public API change

Breaking Changes

None.

Waivers

• Waived: npm run build (squad-sdk) / npm run lint — both fail identically on a clean upstream/dev checkout (verified by stashing this PR's changes and re-running) with 6 pre-existing TypeScript errors in packages/squad-sdk/src/adapter/client.ts (RuntimeConnection not exported by @github/copilot-sdk, CopilotClientOptions.connection, ModelBilling.tokenPrices, CopilotClient.onLifecycle, etc.). This file is untouched by this PR. Requesting a maintainer confirm this is known baseline debt (skip-changelog/reviewer waiver as appropriate — not requesting skip-changelog since a changeset is included).
• Waived: full npm test run — running the complete suite locally (npx vitest run, ~6400 tests, no path filter) produced widespread, unrelated failures across dozens of test files with no relation to this diff (e.g. test/storage-provider.test.ts, test/session-adapter.test.ts, test/scripts/check-shebang-eol.test.ts), consistent with local resource contention under full parallelism rather than a real regression. Also observed: at least one test in this run (apparently a self-upgrade/dogfooding test) wrote to this checkout's own .squad/config.json and .github/agents/squad.agent.md; both were reverted before committing and are not part of this PR's diff. Given the risk of further side effects against this real checkout, I did not force a full run to completion. All targeted and directly-adjacent suites (see above) pass. Requesting CI be the source of truth for the full-suite gate on this PR.
• Waived: test/init-scaffolding.test.ts intermittent failure under combined load — no-remote resilience (#579) > initSquad/runInit succeeds in a git repo with no remote and a doctor sub-test flip between pass/fail depending on what else is running concurrently; the full file passes 26/26 in isolation on two separate runs. Not caused by this change (no code in this diff is exercised by that test).

Do not link/close #1589 — related area but a different bug.