feat(indicators): A5a Fibonacci tools (price-level) (#171)

Adds the six price-level Fibonacci tools as a new **Fibonacci** family (catalogue 367 -> 373, twenty-four families). All build on the internal `pattern_swing` ZigZag tracker, are parameter-free (baked 5% swing threshold), and emit `Candle -> struct` outputs via custom Python/Node/WASM bindings.

| Tool | Output |
|------|--------|
| `FibRetracement` | seven levels (0/23.6/38.2/50/61.8/78.6/100%) of the last swing leg |
| `FibExtension` | five extension ratios (127.2/141.4/161.8/200/261.8%) projected beyond the leg |
| `FibProjection` | A-B-C measured-move target zone (61.8/100/161.8/261.8%) |
| `AutoFib` | retracement anchored on the dominant (largest-magnitude) recent leg |
| `GoldenPocket` | the 0.618-0.65 optimal-trade-entry band (low/mid/high) |
| `FibConfluence` | densest cluster of retracement levels across recent legs (price + strength) |

Fully wired: core (100% unit-tested branches), Python/Node/WASM struct bindings, fuzz driver, reference + streaming-vs-batch tests, README/docs counter. The four geometric/time tools (Fan, Arcs, Channel, Time Zones) follow in A5b.

Verification: `cargo test --workspace` green, clippy `-D warnings` clean, node 450 tests, python 760 tests.

bindings/node/index.d.ts

@@ -362,6 +362,46 @@ export interface OvernightIntradayReturnValue {
   overnight: number
   intraday: number
 }
+export interface FibRetracementValue {
+  level0: number
+  level236: number
+  level382: number
+  level500: number
+  level618: number
+  level786: number
+  level1000: number
+}
+export interface FibExtensionValue {
+  level1272: number
+  level1414: number
+  level1618: number
+  level2000: number
+  level2618: number
+}
+export interface FibProjectionValue {
+  level618: number
+  level1000: number
+  level1618: number
+  level2618: number
+}
+export interface AutoFibValue {
+  level0: number
+  level236: number
+  level382: number
+  level500: number
+  level618: number
+  level786: number
+  level1000: number
+}
+export interface GoldenPocketValue {
+  low: number
+  mid: number
+  high: number
+}
+export interface FibConfluenceValue {
+  price: number
+  strength: number
+}
 export type SmaNode = SMA
 export declare class SMA {
   constructor(period: number)
@@ -3832,3 +3872,57 @@ export declare class OvernightIntradayReturn {
   isReady(): boolean
   warmupPeriod(): number
 }
+export type FibRetracementNode = FibRetracement
+export declare class FibRetracement {
+  constructor()
+  update(high: number, low: number): FibRetracementValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type FibExtensionNode = FibExtension
+export declare class FibExtension {
+  constructor()
+  update(high: number, low: number): FibExtensionValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type FibProjectionNode = FibProjection
+export declare class FibProjection {
+  constructor()
+  update(high: number, low: number): FibProjectionValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type AutoFibNode = AutoFib
+export declare class AutoFib {
+  constructor()
+  update(high: number, low: number): AutoFibValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type GoldenPocketNode = GoldenPocket
+export declare class GoldenPocket {
+  constructor()
+  update(high: number, low: number): GoldenPocketValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}
+export type FibConfluenceNode = FibConfluence
+export declare class FibConfluence {
+  constructor()
+  update(high: number, low: number): FibConfluenceValue | null
+  batch(high: Array<number>, low: Array<number>): Array<number>
+  reset(): void
+  isReady(): boolean
+  warmupPeriod(): number
+}