amber-lsp library rule packs: Grant tenancy detected from source (v2)

[crimson-knight]

Library rule packs for amber-lsp, v2 (reworked after owner review).

What changed from v1

• No shard.yml declaration. v1 made apps declare grant: tenancy: row in shard.yml; shard.yml is a package manifest, so that is removed. The tenancy mode is now detected from the app's own Crystal source with the Crystal parser: row mode = a model's multitenant :col macro (the column is captured per model, never assumed to be tenant_id); schema mode = Grant::SchemaTenant.with / schema_tenant_excluded.
• Packs live at lib/<shard>/.amber-lsp/packs/*.yml (was .claude/rules/, which belongs to Claude Code). Harness-neutral: the same diagnostics reach Claude Code and Codex.
• Rules target only what Grant cannot catch at runtime. Grant already raises NoTenantError, ScopedRawSqlError, and TenantMismatchError, so those checks are gone.

Grant tenancy pack (ships in Grant, branch luna/tenancy-pack-v2)

Two errors (block agent edits through the fleet gate):

• grant/chained-unscoped-in-request-code: chainable Model.unscoped (no block) returns an unguarded builder; in controllers/channels/sockets/pipes.
• grant/chained-unscoped-bulk-write: Model.unscoped...update_all/delete_all outside spec/ and db/ (silently writes every tenant's rows).

Eight warnings: chainable unscoped elsewhere, block unscoped in request code, spawn inside a tenant block (fiber loses the tenant), a tenant column without multitenant, raw connection SQL naming a tenant table, Tenant.clear in app code, schema-mode queries outside SchemaTenant.with in non-request code, both modes present.

Verification

• crystal-alpha spec spec/amber_lsp: 233 examples, 0 failures; full suite 436, 0 failures.
• crystal-alpha build --no-codegen src/amber_lsp.cr: GREEN. tool format --check: clean.
• End-to-end: built amber-lsp + amber-lsp-check on a probe app with multitenant :account_id — Invoice.unscoped.delete_all in a controller produced both errors (exit 1); spawn in a tenant block produced the warning.
• The fixture pack is byte-identical to Grant's pack.

Draft until the Grant tenancy branch lands (the pack describes Grant as of luna/final).