[logger]: Add zerolog-backed logger package

[pseudomuto]

The proxy logged through go.temporal.io/server/common/log, which dragged in the entire Temporal server module (and its transitive deps) just for a logging interface. That is a heavy dependency to carry for the small slice of functionality actually used.

Add pkg/logger that defines a small leveled, structured Logger interface with a zerolog-backed implementation (plus noop and test loggers). The tag subpackage structures key/value pairs.

The package also exposes a configurable default logger and package-level helpers for callers that do not thread a Logger through.

[Copilot]

Pull request overview

Adds a lightweight in-repo logging abstraction to avoid depending on go.temporal.io/server/common/log (and the full Temporal server module) for the proxy’s logging needs.

Changes:

• Introduces pkg/logger (level + structured Logger interface) with a zerolog-backed implementation plus noop and in-memory test loggers.
• Adds pkg/logger/tag for typed key/value structured fields.
• Migrates server wiring and CLI startup logging to the new logger and updates module dependencies (go.mod/go.sum) accordingly.

Reviewed changes

Copilot reviewed 18 out of 19 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pkg/logger/zero.go	Adds ZeroLogger implementation backed by zerolog.
pkg/logger/zero_test.go	Tests level filtering, tags, and With() behavior for ZeroLogger.
pkg/logger/test.go	Adds in-memory TestLogger for assertions in tests.
pkg/logger/test_test.go	Tests TestLogger recording, With() chaining/sharing, and concurrency safety.
pkg/logger/tag/tag.go	Defines Tag and helper constructors (String, Component, Error, Stringer).
pkg/logger/tag/tag_test.go	Tests tag helper constructors.
pkg/logger/tag/doc.go	Package docs for tag.
pkg/logger/noop.go	Adds NoopLogger implementation.
pkg/logger/noop_test.go	Tests NoopLogger behavior (no panics, With identity).
pkg/logger/logger.go	Defines Logger interface, levels, default logger, and package-level helpers.
pkg/logger/logger_test.go	Tests ParseLevel.
pkg/logger/doc.go	Package docs for logger.
internal/server/server.go	Switches server logging from Temporal server logger to pkg/logger.
internal/server/server_test.go	Updates server tests to use logger.TestLogger instead of an ad-hoc recorder.
internal/server/fx.go	Updates fx params/wiring to accept optional logger.Logger.
internal/server/fx_test.go	Updates fx test to provide logger.NewNoopLogger().
cmd/proxy/serve.go	Creates and provides a ZeroLogger from CLI flags; updates startup error logging.
go.mod	Drops go.temporal.io/server; adds github.com/rs/zerolog.
go.sum	Updates sums to reflect dependency changes (remove Temporal server transitive deps, add zerolog deps).