[SC-16731] Rename constitution to charter everywhere

[even-steven]

What and why?

Renames the term "constitution" to "charter" consistently across the entire Atryum codebase — Go backend, TypeScript/TSX UI, database schema, docs, and skill files.

Also removes the "User pattern" field from the rule scope UI in the Invocations page (it was always * / not useful).

Before: constitution, constitution_field_key throughout code, DB columns, API JSON, and UI labels.
After: charter, charter_field_key throughout — a cleaner, more intuitive term for the agent governance document.

How to test

1. Run migrations — 021_rename_constitution_to_charter should apply cleanly on a fresh or existing DB.
2. Open Settings UI → Agent Record Sync section should show "Charter Field" label.
3. Open Agents UI → agent detail panel should show "Charter" textarea.
4. Verify an AI evaluation rule still fires correctly end-to-end (requires companion backend PR).

What needs special review?

• DB migration 021 renames two columns using ALTER TABLE ... RENAME COLUMN — works on SQLite 3.25+ and all supported Postgres versions.
• The Go SyncSettingsProvider interface method renamed from ConstitutionFieldKey to CharterFieldKey — all implementations updated.
• JSON tags on API request/response structs changed (constitution_field_key → charter_field_key) — requires the companion backend PR to land together.

Dependencies, breaking changes, and deployment notes

Companion backend PR required: The VM backend POST /atryum/evaluate endpoint must be updated to read charter_field_key instead of constitution_field_key. See companion PR in validmind/backend.

Breaking change for any external callers of the Atryum API that pass constitution or constitution_field_key fields — those must be updated to charter / charter_field_key.

Release notes

Renames the agent governance document from "constitution" to "charter" throughout the Atryum UI and API.

Checklist

• What and why
• How to test
• What needs special review
• Dependencies, breaking changes, and deployment notes
• Labels applied
• PR linked to Shortcut
• Tested locally

Made with Cursor

[shortcut-integration]

This pull request has been linked to Shortcut Story #16731: Unify language.

[mdeyell-valid-mind]

The db test needs to be updated

--- FAIL: TestMigrationRegistryPreservesExistingVersionsAndNames (0.00s)
    db_test.go:50: migration count = 21
--- FAIL: TestGetPendingMigrationsUsesRegistryOrder (0.00s)
    db_test.go:88: pending count = 20
--- FAIL: TestInitDB_FreshDatabase (0.01s)
    sqlite_test.go:45: expected 20 migrations, got 21
--- FAIL: TestInitDB_Idempotent (0.01s)
    sqlite_test.go:74: expected 20 migrations after double init, got 21

[mdeyell-valid-mind]

grep still shows user_pattern in a couple places