Add enterprise docs structure and include pending core maintenance updates.

docs/troubleshooting.md

@@ -0,0 +1,62 @@
+# Troubleshooting
+
+## Build And Test Failures
+
+### Symptom
+`dotnet build` or `dotnet test` fails locally or in CI.
+
+### Checks
+1. Verify .NET 10 SDK is installed.
+2. Run `dotnet restore`.
+3. Run `dotnet format --verify-no-changes`.
+4. Re-run tests with `dotnet test CBDD.slnx -c Release`.
+
+### Resolution
+- Fix reported compile/test failures before merge.
+- For flaky tests, isolate affected test class and open an issue with reproduction details.
+
+## Data File And Recovery Issues
+
+### Symptom
+Database startup fails or recovery path throws WAL/storage errors.
+
+### Checks
+1. Capture exact exception and stack trace.
+2. Reproduce with storage/recovery-focused tests.
+3. Validate rollback path from [`deployment.md`](deployment.md#rollback-procedure).
+
+### Resolution
+- Pin consumers to last known-good package.
+- Apply fix and add regression coverage in recovery/transaction tests.
+
+## Query And Index Issues
+
+### Symptom
+Unexpected query performance or incorrect query results.
+
+### Checks
+1. Verify relevant indexes are configured for query predicates.
+2. Reproduce with test cases in `tests/CBDD.Tests` for query/index modules.
+3. Validate behavior for scan fallback and expression translation.
+
+### Resolution
+- Add or adjust index definitions and query tests.
+- Document any changed query semantics in release notes.
+
+## Source Generation Issues
+
+### Symptom
+Generated mappers missing or serialization behavior differs from expectations.
+
+### Checks
+1. Verify entity attributes and accessibility are valid for source generation.
+2. Build solution to regenerate mapper output.
+3. Validate related tests in source generator test coverage.
+
+### Resolution
+- Update entity annotations or generator logic.
+- Add focused regression tests for unsupported pattern handling.
+
+## Escalation
+
+If troubleshooting steps do not resolve the issue, follow incident escalation in [`runbook.md`](runbook.md).