Description

In the Liquidity Launchpad introduction page, there's a broken link for "custom strategies".

File: docs/contracts/liquidity-launchpad/01-introduction.md

Line 36:

**Liquidity Strategies** - Modular contracts for different price discovery and liquidity mechanisms (prebuilt [LBP Strategy](https://github.com/Uniswap/liquidity-launcher) or [custom strategies](quickstarts/building.md))

The link quickstarts/building.md points to a file that doesn't exist, resulting in a 404 error.

Expected Behavior

The link should either:

1. Point to an existing documentation page about building custom strategies
2. Be removed if no such documentation exists yet
3. Link to an external resource (e.g., GitHub repo) if applicable

Steps to Reproduce

1. Navigate to the Liquidity Launchpad Overview page
2. Click on "custom strategies" link in the Core Components section
3. Observe 404 error