refactor!: use Arc internally in Database

[m4tx]

This makes the API more ergonomic, as Arc should really just be an implementation detail, rather than something exposed to the user.

This is a followup to the discussion here:
#419 (comment)

[Copilot]

Pull request overview

This PR refactors the Database type to use Arc internally rather than exposing it in the public API, making the framework more ergonomic for users. The change treats reference counting as an implementation detail rather than a user concern.

• Moved Arc wrapping inside Database struct and added Clone implementation
• Removed RequestDb extractor in favor of direct Database extraction via FromRequestHead
• Updated all type signatures throughout the codebase from Arc<Database> to Database

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
cot/src/db.rs	Core refactoring: wraps DatabaseImpl in Arc internally, adds Clone derive, updates all match expressions to dereference the Arc, removes redundant DatabaseBackend impl for Arc<Database>
cot/src/request/extractors.rs	Removes RequestDb wrapper struct and implements FromRequestHead directly on Database type
cot/src/request.rs	Updates RequestExt trait method signatures to return &Database instead of &Arc<Database>
cot/src/project.rs	Updates all type signatures and trait bounds from Arc<Database> to Database throughout bootstrap and context types
cot/src/session/store/db.rs	Updates DbStore to store Database instead of Arc<Database>, removes unused Arc import
cot/src/auth/db.rs	Updates DatabaseUserBackend to store Database instead of Arc<Database>, removes unused Arc import
cot/src/test.rs	Updates TestDatabase and TestRequestBuilder to use Database instead of Arc<Database> throughout
cot/src/openapi.rs	Updates ApiOperationPart implementation from RequestDb to Database
examples/todo-list/src/main.rs	Updates handler signatures to use db: Database extractor instead of RequestDb(db): RequestDb, adds Database to imports, removes RequestDb import
examples/forms/src/main.rs	Updates handler signatures to use db: Database extractor instead of RequestDb(db): RequestDb, adds Database to imports, removes RequestDb import
examples/admin/src/main.rs	Updates handler signatures to use db: Database extractor instead of RequestDb(db): RequestDb, adds Database to imports, removes RequestDb import

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[github-actions]

Bencher Report

Branch	arc-database
Testbed	github-ubuntu-latest

Click to view all benchmark results

Benchmark	Latency	Benchmark Result microseconds (µs) (Result Δ%)	Upper Boundary microseconds (µs) (Limit %)
empty_router/empty_router	📈 view plot 🚷 view threshold	6,064.30 µs (+0.10%) Baseline: 6,058.53 µs	6,795.29 µs (89.24%)
json_api/json_api	📈 view plot 🚷 view threshold	1,039.80 µs (+1.50%) Baseline: 1,024.45 µs	1,131.99 µs (91.86%)
nested_routers/nested_routers	📈 view plot 🚷 view threshold	951.80 µs (+0.49%) Baseline: 947.18 µs	1,042.46 µs (91.30%)
single_root_route/single_root_route	📈 view plot 🚷 view threshold	914.14 µs (+0.80%) Baseline: 906.84 µs	995.54 µs (91.82%)
single_root_route_burst/single_root_route_burst	📈 view plot 🚷 view threshold	17,438.00 µs (-1.56%) Baseline: 17,715.17 µs	20,867.06 µs (83.57%)

🐰 View full continuous benchmarking report in Bencher

[seqre]

LGTM

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated no new comments.

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