fix(shared-context): edition 2024 for let-chains + Option/Result coercion in registry_guard

The 2026-05-25 migration introduced let-chains syntax into shared-context
(exclusion_registry.rs, registry_guard.rs, storage.rs) but left
shared-context/Cargo.toml at edition = "2021", so local builds of every
fleet bot fail with "let chains are only allowed in Rust 2024 or later".

Additionally, registry_guard.rs:127 was calling
.and_then(|r| r.url().map(|s| s.to_string())) on git2::Remote::url()
which returns Result<&str, Error> (not Option<&str>), producing an
Option/Result type mismatch. The same buggy line was duplicated in
robot-repo-automaton/src/registry_guard.rs:131.

Changes:
- shared-context/Cargo.toml: edition 2021 -> 2024 (rustc 1.85+; CI uses
  dtolnay/rust-toolchain@stable which already supports it)
- shared-context/src/registry_guard.rs:126: insert .ok() between
  r.url() and the .map(|s| s.to_string()) to coerce Result to Option
- robot-repo-automaton/src/registry_guard.rs:131: same .ok() fix

Verified locally with cargo check on:
  shared-context, robot-repo-automaton, dashboard, shared-context/fleet-cli,
  bots/{accessibilitybot,cipherbot,echidnabot,finishingbot,glambot,gsbot,
        panicbot,rhodibot,seambot,the-hotchocolabot}

Pre-existing unrelated break (out of scope): bots/sustainabot has a
path dependency on bots/panic-attacker/ which does not exist in-tree.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

robot-repo-automaton/src/registry_guard.rs

@@ -128,7 +128,7 @@ fn repo_identity(repo_path: &Path) -> (Option<String>, Option<String>) {
     let origin_url = repo
         .find_remote("origin")
         .ok()
-        .and_then(|r| r.url().map(|s| s.to_string()));
+        .and_then(|r| r.url().ok().map(|s| s.to_string()));
     let full_name = origin_url.as_deref().and_then(parse_full_name);
     (full_name, origin_url)
 }

shared-context/Cargo.toml

@@ -2,7 +2,7 @@
 [package]
 name = "gitbot-shared-context"
 version = "0.1.0"
-edition = "2021"
+edition = "2024"
 authors = ["Hyperpolymath <dev@hyperpolymath.org>"]
 description = "Shared context layer for gitbot-fleet coordination"
 license = "MPL-2.0"

shared-context/src/registry_guard.rs

@@ -123,7 +123,7 @@ fn repo_identity(repo_path: &Path) -> (Option<String>, Option<String>) {
     let origin_url = repo
         .find_remote("origin")
         .ok()
-        .and_then(|r| r.url().map(|s| s.to_string()));
+        .and_then(|r| r.url().ok().map(|s| s.to_string()));
     let full_name = origin_url.as_deref().and_then(parse_full_name);
     (full_name, origin_url)
 }