Expand model tag support: add GLM-5.1, simplify Anthropic IDs, scan tags anywhere in message

- Flink update_bars debouncing
- update_bars subscription idempotency bugfix
- Price decimal correction bugfix of previous commit
- Add GLM-5.1 model tag alongside renamed GLM-5
- Use short Anthropic model IDs (sonnet/haiku/opus) instead of full version strings
- Allow @tags anywhere in message content, not just at start
- Return hasOtherContent flag instead of trimmed rest string
- Only trigger greeting stream when tag has no other content
- Update workspace knowledge base references to platform/workspace and platform/shapes
- Hierarchical knowledge base catalog
- 151 Trading Strategies knowledge base articles
- Shapes knowledge base article
- MutateShapes tool instead of workspace patch

gateway/knowledge/trading/strategies/stocks/event-driven-ma.md

@@ -0,0 +1,50 @@
+---
+description: "Captures excess returns from merger arbitrage (M&A) by taking long positions in target company stock and, for stock mergers, short positions in the acquirer, exploiting the spread between current and deal prices."
+tags: [stocks, event-driven, merger-arbitrage, risk-arbitrage]
+---
+
+# Event-Driven — M&A
+
+**Section**: 3.16 | **Asset Class**: Stocks | **Type**: Event-Driven / Arbitrage
+
+## Overview
+This strategy, also known as "merger arbitrage" or "risk arbitrage", attempts to capture excess returns generated via corporate actions such as mergers and acquisitions (M&A). When one publicly traded company announces the acquisition of another, a spread typically exists between the target's current market price and the proposed deal price. The trader seeks to profit from this spread closing at deal completion.
+
+## Construction / Signal
+A merger arbitrage opportunity arises when a publicly traded acquirer announces intent to buy a publicly traded target at a price differing from the target's current market price. Two main transaction types:
+
+**Cash merger**:
+- Trader establishes a **long position in the target company stock** only.
+- Profit = (deal price − current target price) if the deal closes.
+
+**Stock merger**:
+- Acquirer offers N_B shares of acquirer stock B for each share of target stock A.
+- Trader **buys 1 share of target A** and **shorts N_B shares of acquirer B**.
+- Example: Current price of A = $67, current price of B = $35, exchange ratio = 2 shares of B per share of A.
+  - Initial net credit = 2 × $35 − $67 = $3 per share of A bought.
+  - This $3 is the profit if the deal closes.
+  - If the deal falls through, the trader will likely lose money.
+
+## Entry / Exit Rules
+- **Entry**: After public announcement of a merger/acquisition deal, establish the arbitrage position (long target, short acquirer for stock mergers).
+- **Exit — deal closes**: Positions are settled at deal terms; long position in target delivers the deal price; the profit is locked in.
+- **Exit — deal breaks**: Close positions at market prices; the spread typically widens sharply on deal failure, resulting in a loss.
+- **Stop-loss**: Discretionary; deal-break risk is the primary risk.
+
+## Key Parameters
+- **Deal spread**: Difference between current target price and proposed deal price (or equivalent in stock merger terms)
+- **Exchange ratio (stock mergers)**: Number of acquirer shares per target share
+- **Merger type**: Cash vs. stock merger (determines position structure)
+- **Holding period**: Duration from announcement to deal close (weeks to months)
+
+## Variations
+- **Long-only (cash merger)**: Buy target only; no short leg.
+- **Dollar-neutral (stock merger)**: Long target, short acquirer in ratio given by deal terms.
+- **Index of deals**: Construct a diversified portfolio across multiple live merger situations simultaneously to reduce single-deal risk.
+
+## Notes
+- The primary risk is "deal break risk": if the merger falls through (regulatory rejection, board change, financing failure), the trader typically suffers a loss as the target price drops back toward pre-announcement levels.
+- Expected return = (spread × probability of deal close) − (loss on deal break × probability of break).
+- Transaction costs and financing costs for short positions reduce profitability.
+- Holding period depends on deal timeline: typically weeks to several months.
+- This strategy requires monitoring deal-specific news (regulatory filings, shareholder votes, competing bids).