refactor!: make our own key-value type

[tisonkun]

This closes #215

[Copilot]

Pull request overview

This PR replaces the existing value-bag-based key/value representation with Logforth’s own structured key-value model (Key/Value + borrowed view types), aligning with the goal in #215 to define a first-class “structural logging” viewpoint and enabling more consistent formatting/serialization across layouts, appenders, and bridges.

Changes:

• Replaced value-bag with new logforth_core::kv types (KeyView/ValueView, ValueOwned, map/list support) and updated all Visitor implementations accordingly.
• Updated the log bridge to translate log::kv into Logforth’s KV model, with an optional serde feature path for richer typed capture.
• Adjusted workspace/features (removed value-bag, added bridge-log-serde) and updated examples + CI to use the new feature wiring.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
logforth/Cargo.toml	Adds bridge-log-serde feature wiring for the log bridge with serde support.
layouts/text/src/lib.rs	Updates KV visiting to use KeyView/ValueView.
layouts/logfmt/src/lib.rs	Updates KV visiting to use views; updates built-in KV emission to pass .view() values.
layouts/json/src/lib.rs	Updates KV collection to use view types for JSON serialization.
layouts/google-cloud-logging/src/lib.rs	Updates KV visiting to use KeyView/ValueView.
examples/Cargo.toml	Adds bridge-log-serde feature flag; adjusts example feature requirements and log dev-dep usage.
diagnostics/task-local/src/lib.rs	Updates diagnostic KV visiting to use borrowed/view KV types.
diagnostics/fastrace/src/lib.rs	Updates emitted KVs + tests for the new KV view/owned model.
core/src/str.rs	Adds Deref<Target=str> for RefStr to simplify string access/comparisons.
core/src/record.rs	Adjusts record cloning/default KV initialization to match the new KeyValues API.
core/src/layout/plain_text.rs	Updates plain-text layout KV visitor signature to view types.
core/src/kv.rs	Introduces the new in-house KV data model (Key/Value + view/owned + list/map), plus optional serde serialization.
core/src/diagnostic/thread_local.rs	Updates thread-local diagnostic KV visiting to the new API.
core/src/diagnostic/static_global.rs	Updates static-global diagnostic KV visiting to the new API.
core/Cargo.toml	Removes value-bag and redefines serde feature for core KV serialization.
Cargo.toml	Removes value-bag workspace dep; adjusts log workspace dependency feature configuration.
bridges/log/src/lib.rs	Refactors log bridge KV translation; adds serde-enabled conversion path.
bridges/log/Cargo.toml	Adds serde feature and adjusts log dependency features (kv, std, optional kv_serde).
appenders/opentelemetry/src/lib.rs	Updates KV extraction to map ValueView into OpenTelemetry AnyValue (including list/map).
appenders/journald/src/lib.rs	Updates journald KV visitor signature to view types.
appenders/journald/src/field.rs	Updates field encoding trait impls to accept ValueView.
appenders/fastrace/src/lib.rs	Updates KV collection/storage to use view types with fewer allocations where possible.
appenders/async/src/worker.rs	Renames diagnostic wrapper and updates visitor calls to .view() for owned keys/values.
appenders/async/src/append.rs	Updates diagnostic collection visitor signature to KeyView/ValueView.
.github/workflows/ci.yml	Updates CI example invocation to include bridge-log-serde where required.

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[Copilot]

Pull request overview

Copilot reviewed 26 out of 26 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 26 out of 26 changed files in this pull request and generated 2 comments.

[ariesdevil]

Should we fire a new release for this?

[tisonkun]

@ariesdevil for sure. We'd need a core 0.4 and all subcrates. Also the facade to be 0.30.

Actually, end users shall not touch these internals.

But I'm working on #230 before we cut the next release or it would be a quick breaking.

[ariesdevil]

self.0.fmt(f)

[ariesdevil]

ditto