fix(node): correct scoped permissions wire codec

[ryankert01]

Which issue does this PR address?

Closes #3643

Rationale

The Node SDK could not create or update users with stream- or topic-scoped permissions because its wire codec did not match the canonical Rust permission format.

What changed?

Nested permission serialization omitted the required continuation marker after each topic and stream, so the server rejected any permission payload with a non-empty streams array. The decoder also read continuation markers without advancing past them, which dropped or misaligned multiple entries.

Serialization and deserialization now mirror the Rust codec, and createUser no longer appends a length and payload when permissions are absent. Canonical byte-vector unit tests cover multiple streams and topics, while the user E2E test verifies scoped permissions through create, update, and get.

Local Execution

• Passed
• Pre-commit hooks did not run in the isolated worktree. The following checks were run manually:
  • npm run lint
  • npm run build
  • npm run test:unit (75 passed)
  • node --import @swc-node/register/esm-register --test src/e2e/tcp.user.e2e.ts (9 passed against a local server)
  • cargo test -p iggy_binary_protocol primitives::permissions::tests::roundtrip_with_streams_and_topics -- --exact

AI Usage

1. OpenAI Codex.
2. Investigation, implementation, regression tests, review, and PR description.
3. The generated changes were verified with exact canonical wire vectors, the full Node unit suite, ESLint, the TypeScript build, a live user E2E test, and the canonical Rust permission test.
4. Yes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.55%. Comparing base (5a5bc9a) to head (7c162b8).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3642      +/-   ##
============================================
+ Coverage     73.49%   73.55%   +0.06%     
  Complexity      937      937              
============================================
  Files          1291     1291              
  Lines        141568   141575       +7     
  Branches     117128   117135       +7     
============================================
+ Hits         104046   104139      +93     
+ Misses        34300    34212      -88     
- Partials       3222     3224       +2     

Components	Coverage Δ
Rust Core	73.71% <ø> (ø)
Java SDK	62.44% <ø> (ø)
C# SDK	72.21% <ø> (ø)
Python SDK	92.17% <ø> (ø)
PHP SDK	84.29% <ø> (ø)
Node SDK	92.37% <100.00%> (+1.01%)	⬆️
Go SDK	42.28% <ø> (ø)

Files with missing lines	Coverage Δ
foreign/node/src/wire/user/create-user.command.ts	100.00% <100.00%> (ø)
foreign/node/src/wire/user/permissions.utils.ts	100.00% <100.00%> (+26.72%)	⬆️

... and 1 file with indirect coverage changes

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