See each listing's days on market and its price history on the listing, the seller report and the weekly seller update #87

Intent: the first two things a seller asks in a meeting are "how long have we been on the market" and "what has the price done"; the app should answer both without the agent doing arithmetic.

Done looks like:

• A small module (src/market.ts, one concept, plain data in and out) computes days on market from the date the listing went active (Coming soon days do not count; a Back on market resumes the count from the original list date, as MLS does) and stops counting at Under contract, Sold, Withdrawn or Expired.
• Each price change is recorded with its date (original list price, every Price improvement, and the sold price), kept under FORGE_APP_DATA via a migration in src/db.ts; existing listings get one entry from their current price and was_price where present.
• The listing page shows "N days on market" and a short price history (date, price, change); the home list shows the day count beside each active listing.
• The printed seller launch report and the weekly seller update email include the day count and the price history.
• The sample listings show believable numbers on first boot (412 Alder Lane at least has one price improvement in its history).
• Tests: the day count across Coming soon, Back on market and Sold transitions with a fixed clock; the history after two price changes; the pages contain both. Every value is escaped. bun test passes and the speed test still holds.
• README's "For the agent" section says where to see days on market and price history.

Files: src/market.ts (new) and its test, src/db.ts, src/listing.ts, src/routes.ts (the status and price actions record the change), src/pages/listing.ts, src/pages/home.ts, src/pages/report.ts, src/update.ts, src/sample.ts, README.md. Risks: #81 (showings) also edits the home list and the listing page; rebase on it if it lands first. Use dates, not timestamps, so a listing launched today reads "0 days", not a negative or fractional count across time zones. Fits: a builder.

Reviewed pull #90 at its head: ticked A small module (src/market.ts, one concept, plain data in and out) computes days on market from the date the listing went active (Coming soon days do not count; a Back on market resumes the count from the original list date, as MLS does) and stops counting at Under contract, Sold, Withdrawn or Expired.; Each price change is recorded with its date (original list price, every Price improvement, and the sold price), kept under FORGE_APP_DATA via a migration in src/db.ts; existing listings get one entry from their current price and was_price where present.; The listing page shows "N days on market" and a short price history (date, price, change); the home list shows the day count beside each active listing.; The printed seller launch report and the weekly seller update email include the day count and the price history.; The sample listings show believable numbers on first boot (412 Alder Lane at least has one price improvement in its history).; Tests: the day count across Coming soon, Back on market and Sold transitions with a fixed clock; the history after two price changes; the pages contain both. Every value is escaped. bun test passes and the speed test still holds.; README's "For the agent" section says where to see days on market and price history..