Reclassify 4 markers that did not match their actual urgency per
docs/development.md:
TODO → XXX (someday-maybe, no commitment):
vendor/cordis/src/reflect.ts:250 — enhance error message
packages/bash-local/src/run.ts:248 — stateful-shell design reference
FIXME → TODO (should fix soon, not blocking release):
vendor/loader/src/index.ts:108 — merge config
vendor/cordis/src/fiber.ts:376 — internal/fiber-info
tsconfig.base.json adds noUncheckedIndexedAccess,
exactOptionalPropertyTypes, noImplicitOverride,
noFallthroughCasesInSwitch, noUnusedLocals, and noUnusedParameters on
top of strict. Vendored packages opt out of the new flags locally
(their tsconfigs are ours to regenerate; their source is not), keeping
upstream-sync friendliness.
Our code fixed accordingly: index accesses acknowledge undefined
(assembler flush cursors, lastTurnNumber); optional properties are
omitted instead of set-to-undefined (GenerateResult.usage,
ToolDefinition.strict, GenerateOptions.system/tools, error payloads
via an errorData helper); Session.onAppend is explicitly
`(…) => void | undefined`; tests and examples updated for unused
parameters and indexed access.