feat(turn): add TCP TURN client example and expose server/local addr

[nightness]

Summary

• Add examples/turn_client_tcp.rs demonstrating TURN relay over TCP
• Expose turn_server_addr() and local_addr() accessors on the TURN client
• Enables TCP fallback when UDP TURN is blocked (common in corporate firewalls)

Review feedback addressed

• Replace unwrap() on --log-level parse with friendly error
• Use split_once('=') for --user to avoid panic on malformed input
• Simplify ctrlc handler: unbounded channel, no thread wrapper
• Extract turn_server_addr_or_err() helper to deduplicate repeated pattern
• cargo fmt / cargo clippy pass clean
• Fix invalid email TLD in clap author metadata
• Fix non-blocking write_all() WouldBlock risk: use blocking writes with timeout
• Fix EOF handling: read_tcp_input() now returns Err on EOF to break main loop
• Add unit tests for turn_server_addr(), turn_server_addr_or_err(), local_addr()

Test plan

• cargo build --example turn_client_tcp -p rtc-turn
• cargo test -p rtc-turn (39 tests pass, including 5 new accessor tests)
• Run against a TURN server with TCP support

Generated with Claude Code

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a TCP-based TURN client example and exposes client address accessors to support TURN-over-TCP fallback scenarios (e.g., UDP blocked by corporate firewalls).

Changes:

• Added turn_client_tcp example demonstrating TURN relay over TCP with RFC4571 framing.
• Exposed Client::turn_server_addr() and Client::local_addr() accessors.
• Updated internal call sites to handle turn_server_addr() now returning Option<SocketAddr>.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
rtc-turn/src/client/relay.rs	Updates TURN server address retrieval to handle Option and map to ErrNilTurnSocket.
rtc-turn/src/client/mod.rs	Exposes turn_server_addr() / local_addr() publicly and adjusts transactions to use the new return type.
rtc-turn/examples/turn_client_tcp.rs	New example implementing TURN client over TCP (RFC6062) with RFC4571 framing.
rtc-turn/Cargo.toml	Registers the new turn_client_tcp example target.

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 143 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.07%. Comparing base (9feb4a3) to head (0303927).

Files with missing lines	Patch %	Lines
rtc-turn/examples/turn_client_tcp.rs	0.00%	138 Missing ⚠️
rtc-turn/src/client/relay.rs	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #83      +/-   ##
==========================================
- Coverage   71.17%   71.07%   -0.10%     
==========================================
  Files         442      443       +1     
  Lines       67330    67468     +138     
==========================================
+ Hits        47922    47953      +31     
- Misses      19408    19515     +107     

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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[nightness]

Rebased onto upstream/master so this PR contains only its own changes. Previous branch structure caused merge conflicts when PRs were merged in sequence. Each PR is now independently mergeable.