feat(parse): expand date vocabulary with named dates

Problem: the date input only supports today, tomorrow, +Nd, and
weekday names, lacking relative offsets like weeks/months, period
boundaries, ordinals, month names, and backdating.

Solution: add yesterday, eod, sow/eow, som/eom, soq/eoq, soy/eoy,
+Nw, +Nm, -Nd, -Nw, ordinals (1st-31st), month names (jan-dec),
and later/someday to resolve_date(). Add tests for all new tokens.

spec/parse_spec.lua

@@ -154,6 +154,171 @@ describe('parse', function()
       local result = parse.resolve_date('')
       assert.is_nil(result)
     end)
+
+    it("returns yesterday's date for 'yesterday'", function()
+      local expected = os.date('%Y-%m-%d', os.time() - 86400)
+      local result = parse.resolve_date('yesterday')
+      assert.are.equal(expected, result)
+    end)
+
+    it("returns today's date for 'eod'", function()
+      local result = parse.resolve_date('eod')
+      assert.are.equal(os.date('%Y-%m-%d'), result)
+    end)
+
+    it('returns Monday of current week for sow', function()
+      local result = parse.resolve_date('sow')
+      assert.is_not_nil(result)
+      local y, m, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      local t = os.time({ year = tonumber(y), month = tonumber(m), day = tonumber(d) })
+      local wday = os.date('*t', t).wday
+      assert.are.equal(2, wday)
+    end)
+
+    it('returns Sunday of current week for eow', function()
+      local result = parse.resolve_date('eow')
+      assert.is_not_nil(result)
+      local y, m, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      local t = os.time({ year = tonumber(y), month = tonumber(m), day = tonumber(d) })
+      local wday = os.date('*t', t).wday
+      assert.are.equal(1, wday)
+    end)
+
+    it('returns first day of current month for som', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = string.format('%04d-%02d-01', today.year, today.month)
+      local result = parse.resolve_date('som')
+      assert.are.equal(expected, result)
+    end)
+
+    it('returns last day of current month for eom', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = os.date('%Y-%m-%d', os.time({ year = today.year, month = today.month + 1, day = 0 }))
+      local result = parse.resolve_date('eom')
+      assert.are.equal(expected, result)
+    end)
+
+    it('returns first day of current quarter for soq', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local q = math.ceil(today.month / 3)
+      local first_month = (q - 1) * 3 + 1
+      local expected = string.format('%04d-%02d-01', today.year, first_month)
+      local result = parse.resolve_date('soq')
+      assert.are.equal(expected, result)
+    end)
+
+    it('returns last day of current quarter for eoq', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local q = math.ceil(today.month / 3)
+      local last_month = q * 3
+      local expected = os.date('%Y-%m-%d', os.time({ year = today.year, month = last_month + 1, day = 0 }))
+      local result = parse.resolve_date('eoq')
+      assert.are.equal(expected, result)
+    end)
+
+    it('returns Jan 1 of current year for soy', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = string.format('%04d-01-01', today.year)
+      local result = parse.resolve_date('soy')
+      assert.are.equal(expected, result)
+    end)
+
+    it('returns Dec 31 of current year for eoy', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = string.format('%04d-12-31', today.year)
+      local result = parse.resolve_date('eoy')
+      assert.are.equal(expected, result)
+    end)
+
+    it('resolves +2w to 14 days from today', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = os.date(
+        '%Y-%m-%d',
+        os.time({ year = today.year, month = today.month, day = today.day + 14 })
+      )
+      local result = parse.resolve_date('+2w')
+      assert.are.equal(expected, result)
+    end)
+
+    it('resolves +3m to 3 months from today', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = os.date(
+        '%Y-%m-%d',
+        os.time({ year = today.year, month = today.month + 3, day = today.day })
+      )
+      local result = parse.resolve_date('+3m')
+      assert.are.equal(expected, result)
+    end)
+
+    it('resolves -2d to 2 days ago', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = os.date(
+        '%Y-%m-%d',
+        os.time({ year = today.year, month = today.month, day = today.day - 2 })
+      )
+      local result = parse.resolve_date('-2d')
+      assert.are.equal(expected, result)
+    end)
+
+    it('resolves -1w to 7 days ago', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local expected = os.date(
+        '%Y-%m-%d',
+        os.time({ year = today.year, month = today.month, day = today.day - 7 })
+      )
+      local result = parse.resolve_date('-1w')
+      assert.are.equal(expected, result)
+    end)
+
+    it("resolves 'later' to someday_date", function()
+      local result = parse.resolve_date('later')
+      assert.are.equal('9999-12-30', result)
+    end)
+
+    it("resolves 'someday' to someday_date", function()
+      local result = parse.resolve_date('someday')
+      assert.are.equal('9999-12-30', result)
+    end)
+
+    it('resolves 15th to next 15th of month', function()
+      local result = parse.resolve_date('15th')
+      assert.is_not_nil(result)
+      local _, _, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      assert.are.equal('15', d)
+    end)
+
+    it('resolves 1st to next 1st of month', function()
+      local result = parse.resolve_date('1st')
+      assert.is_not_nil(result)
+      local _, _, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      assert.are.equal('01', d)
+    end)
+
+    it('resolves jan to next January 1st', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local result = parse.resolve_date('jan')
+      assert.is_not_nil(result)
+      local y, m, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      assert.are.equal('01', m)
+      assert.are.equal('01', d)
+      if today.month >= 1 then
+        assert.are.equal(tostring(today.year + 1), y)
+      end
+    end)
+
+    it('resolves dec to next December 1st', function()
+      local today = os.date('*t') --[[@as osdate]]
+      local result = parse.resolve_date('dec')
+      assert.is_not_nil(result)
+      local y, m, d = result:match('^(%d+)-(%d+)-(%d+)$')
+      assert.are.equal('12', m)
+      assert.are.equal('01', d)
+      if today.month >= 12 then
+        assert.are.equal(tostring(today.year + 1), y)
+      else
+        assert.are.equal(tostring(today.year), y)
+      end
+    end)
   end)
 
   describe('command_add', function()