wrote readme, updated api

README.md

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+# go-mana-component
+
+Component identity propagation for layered Go libraries.
+
+Source: https://git.wisehodl.dev/jay/go-mana-component
+Mirror: https://github.com/wisehodl/go-mana-component
+
+## What this library does
+
+- Injects a named component identity into a `context.Context` at library boundaries
+- Propagates module identity and component hierarchy across layers
+- Provides `slog` attributes for structured logging and a string map for generic consumers
+
+## What this library does not do
+
+`go-mana-component` does not log, does not define what a module or component
+means semantically, and does not manage component lifecycles or dependencies.
+It only carries identity. Interpretation, enforcement of naming conventions,
+metrics, and tracing instrumentation all belong elsewhere.
+
+## Installation
+
+```bash
+go get git.wisehodl.dev/jay/go-mana-component
+```
+
+If the primary repository is unavailable, use the `replace` directive in your `go.mod`:
+
+```
+replace git.wisehodl.dev/jay/go-mana-component => github.com/wisehodl/go-mana-component latest
+```
+
+## Usage
+
+As an example, the `go-honeybee` library uses a three-layer component hierarchy
+for pools, workers, and connections. To provide structured logging, each
+component accepts a component-aware context and an `slog.Handler` and then
+constructs a logger internally.
+
+### At a library boundary
+
+A top-level constructor receives a context and creates a new component
+identity. Injecting the component attributes on the logger allows it to carry
+`module` and `path` automatically.
+
+```go
+func NewPool(ctx context.Context, id string, handler slog.Handler) (*Pool, error) {
+    ctx = component.MustNew(ctx, "honeybee", "outbound_pool")
+
+    attrs, _ := component.Attrs(ctx)
+    logger := slog.New(handler).WithAttrs(attrs).With(slog.String("pool_id", id))
+
+    return &Pool{ctx: ctx, logger: logger}, nil
+}
+```
+
+### Descending into a sub-component
+
+A child constructor calls `MustExtend`, inheriting the module and extending the
+path. No parent identifiers need to be passed as arguments.
+
+```go
+func NewWorker(ctx context.Context, id string, handler slog.Handler) (*Worker, error) {
+    ctx = component.MustExtend(ctx, "outbound_worker")
+
+    attrs, _ := component.Attrs(ctx)
+    logger := slog.New(handler).WithAttrs(attrs).With(slog.Any("peer_id", id))
+
+    return &Worker{ctx: ctx, logger: logger}, nil
+}
+```
+
+At the connection layer, another `MustExtend` call extends the path to
+`outbound_pool.outbound_worker.connection` with no additional plumbing.
+
+`GetFields` provides the component fields as a `map[string]string` for non-slog
+consumers.
+
+## Testing
+
+```bash
+go test ./...
+```