docs(schema): align agent_ownership / agent_sharing / mcp_api_keys DDL with live schema (#770)

[AndriiPasternak31]

Summary

Doc-only follow-up to #770. Aligns stale DDL blocks in docs/memory/ to reflect src/backend/db/schema.py's current state. No code changes, no schema changes, no migrations.

The structural schema fix already shipped in #712 (fix(schema): backfill schema.py to match migrations.py reality, merged 2026-05-08). Every "Critical" finding from the scheduled /validate-schema report attached to #770 was already resolved by that PR — verified by tests/unit/test_schema_parity.py (4/4 PASS in origin/dev).

What this PR changes

docs/memory/architecture.md, three DDL blocks:

Table	Before	After
agent_ownership	4 of ~25 columns documented; owner_id TEXT, agent_name TEXT PRIMARY KEY	All 25 columns documented; correct PK / FK shape (id AUTOINCREMENT, agent_name UNIQUE, owner_id INTEGER)
agent_sharing	shared_by_id TEXT NOT NULL; missing allow_proactive	shared_by_id INTEGER NOT NULL; allow_proactive added
mcp_api_keys	Wrong column names (last_used, use_count), wrong type (user_id TEXT); missing description, key_prefix, is_active, agent_name, scope	All columns aligned with schema.py:115-131

docs/memory/feature-flows/agent-sharing.md (added in commit d220ee26 after /sync-feature-flows audit):

Table	Before	After
agent_sharing	Missing allow_proactive column	allow_proactive INTEGER DEFAULT 0 added

DDL is descriptive, not byte-exact:

• Doc retains CREATE TABLE, schema.py uses CREATE TABLE IF NOT EXISTS.
• Doc keeps inline annotations (-- CAPACITY-001, -- #311, -- proactive-toggle (Issue #376)) for human readers — these don't exist in schema.py.

Explicit scope-callout

This PR fixes 3 DDL blocks in architecture.md (named in #770's Informational section) plus 1 sibling DDL block in feature-flows/agent-sharing.md surfaced by /sync-feature-flows. 27 other tables in architecture.md also lack DDL blocks compared to schema.py — out of scope, tracked at #787.

Also out of scope (deferred to follow-up issues):

• feature-flows/agent-lifecycle.md references a non-existent table agent_mcp_api_keys. Fix requires prose+DDL coordination, not a one-line edit. Will be filed as its own doc-bug issue.
• feature-flows/autonomy-mode.md shows a partial 10-column agent_ownership DDL — verified intentional (autonomy-scoped); the 10 columns match schema.py exactly.

Follow-ups

1. Decide DDL duplication strategy: keep architecture.md DDL or link to schema.py #786 (Abilityai/trinity, P3) — Decide DDL duplication strategy: keep architecture.md DDL, link to schema.py, or auto-generate. This PR reinforces duplication; Decide DDL duplication strategy: keep architecture.md DDL or link to schema.py #786 is where the long-term call gets made.
2. Doc completeness: 27 tables in schema.py lack DDL blocks in architecture.md #787 (Abilityai/trinity, P3) — Doc completeness for the remaining 27 undocumented tables. Blocked on Decide DDL duplication strategy: keep architecture.md DDL or link to schema.py #786.
3. validate-schema produces false-positive 'critical' findings against already-fixed schema abilities#2 (P1, 2-week SLA, target 2026-05-25) — Fix the /validate-schema skill so it stops auto-filing priority-p1 issues for non-issues. The validator runs on a remote Trinity agent and the skill source lives in abilityai/abilities, so this can't be patched in abilityai/trinity.

A courtesy ping to the vybe remote agent owner (to pause the scheduled run while abilities#2 is open) is in the closing comment on #770.

Verification

$ uv run --with-requirements tests/requirements-test.txt pytest tests/unit/test_schema_parity.py -v
tests/unit/test_schema_parity.py::TestSchemaParity::test_no_missing_tables PASSED
tests/unit/test_schema_parity.py::TestSchemaParity::test_no_missing_columns PASSED
tests/unit/test_schema_parity.py::TestSchemaParity::test_no_missing_indexes PASSED
tests/unit/test_schema_parity.py::TestSchemaParity::test_no_missing_triggers PASSED
======================== 4 passed in 0.26s =========================

Visual diff of every updated block against schema.py lines 67-97 / 99-110 / 115-131 — every column name, type, default, and FK matches (modulo intentional CREATE TABLE vs CREATE TABLE IF NOT EXISTS and retained -- annotations).

Closes

Closes #770 — the structural fix shipped in #712; this PR addresses the named doc drift plus one sibling drift surfaced by /sync-feature-flows.

[vybe]

LGTM — DDL blocks verified against schema.py, clean docs-only change. Merging.