fix(Cargo.toml): remove stale tokio-tungstenite v0.28.0 patch (no-op, false assurance)

The [patch.crates-io] entry for tokio-tungstenite v0.28.0 was inert: the
workspace resolves tokio-tungstenite to 0.21.0 and 0.29.0 (both crates.io),
so Cargo marked the v0.28.0 patch [[patch.unused]] and emitted a "patch was
not used in the crate graph" warning on every build/clippy.

v0.29.0 already includes rustls 0.23.40, which natively fixes
RUSTSEC-2026-0049. The v0.28.0 git patch was a pre-0.29.0 workaround that
created false security assurance — a declared-but-never-applied "fix".

Scope is surgical (7 deletions, 0 additions, 2 files):
- Cargo.toml: delete the tokio-tungstenite comment + patch line.
- Cargo.lock: delete the [[patch.unused]] block for the v0.28.0 git source.
- The unrelated rustls-webpki git patch (RUSTSEC CRL/name-constraint scope)
  is intentionally preserved.

This is the faithful mirror of commit c5119df (the Carthos-validated fix
for the duplicate #2742), re-applied on a pristine branch cut from
origin/main (236d747). Prior branches drifted into contamination
(.docs/.pr2659/.gitignore churn); this branch carries ONLY the patch removal.

Verification:
- cargo clippy --workspace -- -D warnings: exit 0, 0 warnings, no
  "patch not used" warning.
- cargo build -p terraphim_server (tungstenite consumer): exit 0.
- cargo audit: no tokio-tungstenite / RUSTSEC-2026-0049 findings.
- cargo fmt --all --check: clean.
- Diff vs origin/main: exactly 7 deletions, 0 additions.

Refs #2986 (duplicate of #2742)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: Test User

Cargo.lock

@@ -97,8 +97,6 @@ terraphim_service = { version = "1.20.5", registry = "terraphim" }
 # genai patch temporarily disabled to test crates.io 0.6.0 compatibility for v1.20.0 publish chain.
 # genai = { git = "https://github.com/terraphim/rust-genai.git", branch = "merge-upstream-20251103" }
 self_update = { git = "https://github.com/AlexMikhalev/self_update.git", branch = "update-zipsign-api-v0.2" }
-# Security: Patch tokio-tungstenite to use rustls 0.23+ for RUSTSEC-2026-0049
-tokio-tungstenite = { git = "https://github.com/snapview/tokio-tungstenite.git", tag = "v0.28.0" }
 # Security: Patch rustls-webpki to fix RUSTSEC-2026-0049 (CRL bypass), 0098, 0099 (name constraints)
 # Using git source to force version override
 rustls-webpki = { git = "https://github.com/rustls/webpki.git", tag = "v/0.103.12" }