Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/simulator/docs/design/live-backend.md`:
- Line 25: The design document references a dual-factory approach with both a
new `createBackendSimulator` and the existing synchronous factory, but the
actual implementation unified these into a single factory. Update the design
document in the live-backend.md file to describe the unified API where
`createSimulator` itself is now the async, backend-aware factory, and remove
references to a separate `createBackendSimulator` factory. Alternatively, add a
note explaining that the dual-factory design was rejected in favor of the single
unified factory approach documented in the code documentation.

In `@packages/simulator/src/live/LiveBackend.ts`:
- Around line 78-105: The call method in LiveBackend currently calls
consumeSingle() after both pure and impure circuit executions, which causes
inconsistent lifecycle management. Remove the consumeSingle() call from the pure
path where it runs after the fn() result is returned. For the impure path, wrap
the txFn execution and result handling in a try-finally block, moving the
consumeSingle() call into the finally block so it executes regardless of whether
the async txFn call succeeds or rejects. This ensures consumption happens
consistently for all impure calls and doesn't occur for pure calls, preventing
leaked single aliases across failed impure calls.

In `@packages/simulator/src/live/registry.ts`:
- Around line 46-48: The registerLiveBackend function currently silently
overwrites an existing registeredFactory without any warning or check, which can
cause non-deterministic behavior in shared test processes. Add a guard check
before assigning the factory parameter to registeredFactory that throws an error
if a factory is already registered, ensuring that accidental or duplicate
registrations are caught and prevent silent context switching. This will make
the function fail loudly rather than silently replacing the backend factory.

In `@packages/simulator/src/signers/Signers.ts`:
- Around line 95-100: The validation block checking if `this.liveAliases.size >
MAX_LIVE_SIGNERS` is executed regardless of the current mode, which causes
shared option objects to fail in dry mode even though liveAliases is documented
as live-only. Gate this validation by wrapping the entire error-throwing block
in a conditional that checks if the mode is 'live' before executing it, so the
signer-cap validation only enforces the limit when actually running in live
mode.

In `@packages/simulator/test/unit/dependency-wall.test.ts`:
- Around line 40-41: The startsWith(LIVE_DIR) check on line 40 uses string
prefix matching which creates false positives for similarly-named directories,
such as treating src/live2/ as being inside src/live/. Replace the startsWith
check with a more robust path boundary check that ensures LIVE_DIR is followed
by a path separator (forward slash) to prevent forbidden imports from bypassing
this guard and ensure only files actually within the LIVE_DIR directory are
filtered out.

---

Nitpick comments:
In `@packages/simulator/docs/design/live-backend.md`:
- Around line 68-85: The fenced code block displaying the directory structure is
missing a language identifier for proper syntax highlighting. Change the opening
fence marker from ``` to ```text at the beginning of the block that shows the
packages/simulator/src/ directory layout to specify the content type and enable
proper rendering.