docs: add triage tasks for cross-open interop + fail-fast harness policy

TASK-143: Cross-open modification compatibility gap
TASK-144: Cross-platform compat no-skip
TASK-145: Schema evolution no acceptable errors
TASK-146: Fail fast and loud harness policy
TASK-147: Cross-open modification interoperability (hard requirement)

Updated gap backlog to reflect remaining compatibility gaps.

Author: subtleGradient

.tasks/triage/TASK-146-fail-fast-loud-harness.md

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+# TASK-146 — Fail fast and loud across all harnesses (no SKIP / no KNOWN_FAIL / no "acceptable" errors)
+
+## Goal
+Make every harness/test runner fail fast and loud if any assumption, dependency, expectation, or invariant is unmet or invalid.
+
+This turns the harness suite into an *invalidation engine*, not a best-effort report generator.
+
+## Status
+- State: triage
+- Priority: high
+
+## Context
+We discovered multiple places where gaps or missing dependencies can be silently ignored:
+
+1. Cross-open modification compatibility is currently treated as "known limitation" instead of a failing test:
+   - `zig/harness/test-cross-open-parity.sh` reports `KNOWN_FAIL: 3` (XO-003 / XO-004 / XO-006)
+   - These represent real compatibility gaps.
+
+2. Some harnesses SKIP entirely when dependencies are missing:
+   - `zig/harness/test-cross-platform-compat.sh` can print `SKIP: Rust/C extension not found ...` and exit successfully.
+
+3. Some harnesses treat SQL errors as PASS:
+   - `zig/harness/test-schema-evolution.sh` currently logs warnings like `WARN: SQL error (may be expected behavior)` and marks PASS.
+
+The desired posture is:
+- Missing dependency → FAIL with actionable instructions.
+- Known limitation / known fail → FAIL (tracked by task card; not ignored).
+- Error-is-acceptable → replace with explicit expected-reject assertion + post-error invariants.
+
+## Files to Modify
+(Exact scope to confirm during execution; keep tight.)
+- `zig/harness/test-parity.sh` (top-level aggregator: enforce nonzero exit on skipped subtests)
+- `zig/harness/test-cross-open-parity.sh` (remove `KNOWN_FAIL` pathway; make XO gaps real FAIL)
+- `zig/harness/test-cross-platform-compat.sh` (remove silent SKIP; fail with provisioning steps)
+- `zig/harness/test-schema-evolution.sh` (replace "acceptable error" PASS with explicit assertions)
+- Any `zig/harness/test-*.sh` that currently prints `SKIP:` / `SKIPPED:` / `WARN:` and still exits 0
+
+## Acceptance Criteria
+1. Harness discipline
+   - No harness script exits 0 when it printed any of:
+     - `SKIP:` / `SKIPPED:`
+     - `KNOWN_FAIL:` / `KNOWN LIMITATION:`
+     - `WARN:` / "acceptable" errors
+   - Instead, it exits nonzero with a clear, actionable message.
+
+2. Dependency discipline
+   - If a harness requires an oracle extension, sqlite version feature (DROP COLUMN), or other capability:
+     - It either provisions it automatically in a deterministic way, OR
+     - It fails with a single canonical instruction (e.g. `./scripts/update-crsqlite-oracle.sh`).
+
+3. Invariant discipline
+   - Any path that expects a failure (e.g. schema evolution conflicts) asserts:
+     - the error class/message pattern
+     - post-error invariants (no partial apply, expected db_version behavior, schema sanity, clock/changes sanity)
+
+4. Aggregator discipline
+   - `make -C zig test-parity` (or whichever CI entrypoint is canonical) fails if any sub-suite fails or is skipped.
+
+## Parent Docs / Cross-links
+- `AGENTS.md` (Zig testing policy; no sqlite-cr for Zig)
+- `.tasks/triage/TASK-143-cross-open-modification-compat.md`
+- `.tasks/triage/TASK-144-cross-platform-compat-no-skip.md`
+- `.tasks/triage/TASK-145-schema-evolution-no-acceptable-errors.md`
+- `research/zig-cr/92-gap-backlog.md`
+
+## Progress Log
+- 2025-12-21: Created from "zero failures" requirement; codifies fail-fast harness policy.
+
+## Completion Notes
+(Empty until done.)

.tasks/triage/TASK-147-cross-open-modification-interoperability.md

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+# TASK-147 — Implement cross-open modification interoperability (Zig matches Rust/C trigger schema)
+
+## Goal
+Change the Zig implementation to match the Rust/C implementation such that a database created by one implementation can be modified by the other and vice-versa.
+
+This is a hard requirement.
+
+## Status
+- State: triage
+- Priority: highest
+
+## Problem Statement
+Cross-open read-only works, but cross-open modification fails due to trigger schema incompatibility.
+
+Today:
+- Zig-created CRR triggers embed `crsql_pack_columns()` directly in trigger SQL.
+- Rust/C-created CRR triggers call helper functions `crsql_after_insert/update/delete()`.
+
+When the other implementation opens the DB and performs INSERT/UPDATE/DELETE, triggers fire and fail:
+- Rust/C on Zig DB: error like `unsafe use of crsql_pack_columns`
+- Zig on Rust/C DB: error like `no such function: crsql_after_*`
+
+This breaks the interoperability requirement.
+
+## Proposed Direction (implementation sketch)
+Unify on the Rust/C trigger schema and semantics:
+
+1. Add Zig implementations for the Rust/C trigger helper SQL functions:
+   - `crsql_after_insert(table_name, pk_new...)`
+   - `crsql_after_update(table_name, pk_new..., pk_old..., [non_pk_new..., non_pk_old...])`
+   - `crsql_after_delete(table_name, pk_old...)`
+
+2. Update Zig trigger generation to emit triggers that call these helpers (matching `core/rs/core/src/triggers.rs`), instead of embedding `crsql_pack_columns()` in SQL.
+
+3. Ensure Zig can also operate correctly when opening an existing Rust/C-created DB that already has Rust-style triggers.
+
+## Files to Modify
+(Keep tight; finalize during execution.)
+- `zig/src/as_crr.zig` (trigger SQL generation)
+- `zig/src/ffi/init.zig` (register new SQL functions)
+- New or existing Zig implementation files to host the helpers (e.g. `zig/src/local_writes/*.zig` or similar)
+- `zig/harness/test-cross-open-parity.sh` (convert known-fail paths into real assertions)
+
+## Acceptance Criteria
+1. `bash zig/harness/test-cross-open-parity.sh`:
+   - XO-003 PASS
+   - XO-004 PASS
+   - XO-006 PASS
+   - `KNOWN_FAIL: 0`
+   - `FAILED: 0`
+   - `SKIPPED: 0`
+2. Cross-open modification performs real writes and correct metadata changes:
+   - base table reflects modifications
+   - `crsql_db_version()` advances appropriately
+   - `__crsql_clock` / `crsql_changes` reflect those writes
+3. No harness uses sqlite-cr to test Zig extension behavior (must follow `AGENTS.md`).
+
+## Parent Docs / Cross-links
+- `.tasks/triage/TASK-143-cross-open-modification-compat.md` (original gap capture)
+- `zig/harness/test-cross-open-parity.sh`
+- `core/rs/core/src/triggers.rs` (Rust trigger schema)
+- `core/rs/core/src/local_writes/after_{insert,update,delete}.rs` (semantics)
+
+## Progress Log
+- 2025-12-21: Task created from hard requirement: cross-open modification must work both directions.
+
+## Completion Notes
+(Empty until done.)